6. respiration Flashcards
what does cellular respiration involve and additional notes
- cellular respiration involves releasing chemical energy, stored in glucose (food).
- respiration is a series of enzyme controlled reactions.
ATP
- Glucose is the main source of energy, it is converted into ATP.
- ATP is used for all cell processes ( Active transport, respiration, muscle contraction, protein synthesis.
- some energy is always lost as heat, the rest energy is transferred to other chemicals.
- the energy used to join the phosphate to ADP is stored in a high energy band. The energy is now ready for quick release.
- in addition of the phosphates to ADP to form ATP is called phosphorylation.
Respiration and where it takes place
respiration takes place in the presence of oxygen
glucose + oxygen ———— CO2, water, ATP
-respiration takes place in the mitochondria.
stages of respiration
- occurs in the cytoplasm of the cell, glucose is spilt into pyruvate and 2ATP are produced (glycolysis). If oxygen is available then pyruvate will diffuse into the mitochondria.
- occurs in matrix of mitochondria
- occurs in the cristae of the mitochondria
stages 2&3 take the pyruvate from stage 1 and convert it to carbon dioxide, water, 36 ATP molecules. TOTAL = 38 ATP from one glucose molecule.
what is the fermentation pathway
the partial breakdown of glucose in the absence of oxygen. Glycolysis occurs as normal releasing two ATP molecules. But with no oxygen pyruvate cannot diffuse into mitochondria. pyruvate is converted into other molecules dependent on animal/plant.
fermentation in animals
pyruvate is converted into lactic acid. lactic acid results in muscle fatigue which reduces efficacy leading to a cramp.
This process is irreversible once oxygen becomes available to the cells. An oxygen debt builds up, this must be repaid.
fermentation in plants
pyruvate produces ethanol and carbon dioxide.
Because CO2 is a gas & waste product it is lost. Not reversible reaction.
